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IBM announced four PS/2 models during its April 1987 launch: the Model 30, 50, 60, and 80. They ranged dramatically in power and price; on the low end, the Model 30 (roughly equivalent to a PC XT) contained an 8MHz 8086 CPU, 640KB of RAM, and a 20MB hard drive, and retailed for $2295 (about $4642 in 2012 dollars when adjusted for inflation).
The most powerful configuration of the Model 80 came equipped with a 20MHz 386 CPU, 2MB of RAM, and a 115MB hard drive for a total cost of $10,995 (about $22,243 today). Neither configuration included an OS--you had to buy PC-DOS 3.3 for an extra $120 with battery like Apple M7385 Battery , Apple M7385G Battery , Apple M8244 Battery , Apple M8511 Battery , Apple M8665 Battery , Apple M8983 Battery , Apple M9324 Battery , Apple M9324G Battery , Apple M9325 Battery , Apple M9326 Battery , Apple PowerBook G4 17 inch Battery , Apple PowerBook G4 M9462 Battery ($242 today).
The following chart from IBM offers a more detailed view of the systems available during the 1987 launch, and illustrates just how complex the variety could be.
Every unit in the line included at least one feature new to IBM's PC offerings--and the market in general. In the following sections, I'll discuss those new features and how they affected the PC industry.
Integrated I/O Functionality, New Memory Standard
From the IBM PC in 1981 through the PC AT in 1984, IBM preferred to keep a minimum of features in the base unit. Instead, it allowed users to extend their systems with expansion cards that plugged into the internal slots. This meant that a 1981 PC, which shipped with five slots, left little room for expansion when it already contained a graphics card, a disk controller, a serial card, and a printer card--a common configuration at the time.
With the PS/2, IBM chose to integrate many of those commonly used I/O boards into the motherboard itself. Each model in the PS/2 line included a built-in serial port, parallel port, mouse port, video adapter, and floppy controller, which freed up internal slots for other uses.
Computers in the PS/2 series also had a few other built-in advancements, such as the 16550 UART, a chip that allowed faster serial communications (useful when using a modem), as well as 72-pin RAM SIMM (single in-line memory module) sockets. Both items became standard across the industry over time.
PS/2 Keyboard and Mouse Ports
The built-in mouse port I mentioned earlier is worth noting in more detail. Each machine in the PS/2 line included a redesigned keyboard port and a new mouse port, both of which used 6-pin mini-DIN connectors.
IBM intended the mouse, as a peripheral, to play a major part in the PS/2 system. The company promised a new graphical OS (which I'll talk about later) that would compete with the Macintosh in windowing functionality.
Even today, many new PCs ship with "PS/2 connectors" for mice and keyboards, although they have been steadily falling out of fashion in favor of USB ports.